Poison
by PureWaterLily
Summary: His lips are poison. GonKillu.


**A/N:** Such a beautiful thing, the friendship and innocence of two young boys. I feel like messing with them~

.

"What happened?!"

The beer can falls out of Leorio's grasp, as he rushes towards the panicked boy before him.

Killua is drenched in a sheen of sweat, expression wild and helpless. In his arms lies the unconscious body of his best friend.

"It's Gon! I don't know what to do, I-!" His grip tightens, leaving crinkles in the fabric of Gon's clothes.

It is the first time Leorio has ever seen Killua this unravelled. Shaking. Incoherent. Gon cannot get air, but Killua has stopped breathing. Killua is a boy intimately familiar with death. He knows when a life is extinguishing before him, but no, not Gon, he can't let this happen to Gon, he won't let this happen-

Going to Leorio is the right move. He knows the medical community best, knows the location of the correct emergency hospital and which doctors to alert. Gon would never make it had Killua brought him to pediatrics or any of the lesser medical centers.

Halfway into his call for an ambulance, though, Leorio is talking inside an empty room. He looks out the window in time to catch Killua disappearing into the traffic, the heavy indent of his footsteps scattered across the hoods of passing cars.

.

Inside the hospital, the nurses are rushing. Wheeling gurneys, oxygen masks, defibrillators. The overhead lights are harsh, and the air is strong of disinfectants. Despite all the noise and confusion, Killua has pulled himself together. He is giving his full cooperation, answering their questions as quickly and concisely as he can.

Just the two of them. The pier. Twelve minutes ago. Thirteen now. Yes. Yes. No. He doesn't know. No, he does not know why this happened. They were not fighting, they were not running away, they were not held hostage, they were finally out of danger, everything was supposed to be safe and normal again so why- Killua clenches his jaw and chokes down the emotions inside him, focusing on answering their next question.

Food? No, they weren't eating. Up until then, they weren't doing anything. Just talking about some things before-!

The nurse does not look up from her clipboard. "Okay Killua-kun, let's rewind. About food..."

Subconsciously, Killua covers his lips, his eyes wide and searching.

No, it can't be…

"...Killua-kun? Did you hear me? We need to know what you two ate so we can rule out poison."

Killua snaps his eyes shut. God, please no.

The doctor presses her stethoscope against her patient's chest, before examining the loss of color in skin, the strained respiration and tight twitches in muscle. This is not good. Too many variables hang in the air, but if she has to make an educated guess, it is most likely-

"Poison!"

The door is slammed off its hinges, Killua breathing heavily at the entrance. Behind him is a frantic nurse, calling his name to no avail. Instead, his focus is on the doctor. "Poison, check Gon for poison!"

The doctor stands up. "Are you sure?"

Killua looks to the bed, suppressing the tightness in his chest. It could be nothing else. He has dissected the scene through and through. Nothing near Gon was dangerous. Nothing except...

"I'm sure."

.

Time is ticking. They could not afford to get this wrong. Leorio has a firm grip on Killua's shoulders, as he asks him again to calm down. To think carefully. Cross out all other possibilities. And if Gon is indeed poisoned, the doctors would need to know with what.

The room of the second Zoldyck brother is dark except for the illumination of his monitors. Milluki continues to type at his keyboard, ignoring the ringing of his phone. By the tenth ring, he gives in.

"What is it, Gotoh? Tell him I'm busy!" A pause. Milluki scowls. "Fine, put him on."

"What, Kil? They're out. How am I supposed to know. Poison? I don't know, there's hundreds." Milluki reaches for a potato chip. "Well, if you really need to know that bad, ask Illumi. He was the one in charge of your training after all."

Killua clutches the phone harder. Feeling smug, Milluki readies to hang up. He does not expect the conversation to continue after that.

He is wrong.

"Do you have his current number."

A blizzard is ripping through the northern border of the Kakin Kingdom, blanketing the estate in white. A lone vibration echoes across the expansive dining room. Illumi pats his pockets.

"Moshi moshi?" Upon hearing the voice, he beams. "Kil! I didn't think you'd call. Did you change your mind about the job?"

His tone is light-hearted, as are his footsteps in his walk past every corpse. He settles for a seat upon the table, where dishes still lie half-warm.

Illumi tilts his head. "Poison? Well, of course. Still think you should stick to your hands though, much faster, but to each their own. Hm?"

In the shadows of a lamp post is Kalluto. He lowers his phone, starting out at the undulations of water. He wonders how much longer Illumi needs to complete their mission.

"... until I get home, I'm afraid. Your request is not easy. We've injected you with hundreds of them. Even I cannot keep track of each and every-" Illumi blinks. "Sorry, repeat that?"

The clock ticks.

It comes out as a rasp, and barely more audible than the first time around. "I'll do it."

"I'll take the job." Killua steadies the tremble in his hand. "So help me, aniki."

.

Killua does not move from his chair, his hands locked in a vice grip, clutched almost like a prayer. He does not notice the lack of circulation in them; he does not feel anything. He does not see anything.

On the third day, Gon escapes critical condition. It is confirmed to be poison, fourth on the list that Killua provided.

"We got the antidote in before he suffered any major brain damage. He's going to be alright."

The news floods Killua with relief, as he drops his head. His hair hides his eyes.

Leorio pats his shoulder. "You should get some rest too."

Killua blinks, hard. "Yeah."

Over the following days, the room is quiet except for the steady beep of monitors. Gon remains unresponsive. Once or twice, there is a flicker of movement behind his eyelids. These could just be Killua's imagination though, because every time he rushes to the bed and calls out Gon's name, the same silence greets him. Nothing has changed, and Killua is forced to choke back down his hopes.

Killua stays by Gon's bed from then on, and together, they bear through the silence.

Killua stays until he can stay no longer. When he finally does stand up, his footwork is uneven and riddled with fatigue. At the door, he spares Gon one last look.

Hopefully, by the time he gets back, Gon will have awakened. Gon will be healthy again. And once he is, they can go grab barbecue. They can play video games. They can nap in the subway. They can visit Mito on Whale Island. They can set off on another adventure, without a care in the world, without anything but two backpacks and each other.

Gon will be healthy again, and everything can go back to normal.

Everything will be normal again.

Killua leaves clinging onto that idea. He clings on, despite the drumming hollowness it creates inside him.

.

 _Their giggles faded. Gon returned his gaze to the ocean, his feet tiptoed on the lowest bar of the railings._

 _"Say, Killua. Is there anything you want?"_

 _Killua leaned back into his arms. "Nah, nothing's really changed. But that's fine, since I'm having fun in the meantime, travelling with you."_

 _"That's not what I meant."_

 _A blink._

 _"You're a good friend, Killua. You do everything I ask. Even the stupid stuff, I know if I ask, you'll do it."_

 _Gon hopped down, closing the space between them. His expression had changed into one of determination. Yet, his tone remained kind, and his eyes were marked by sincerity._

 _"But you never asked for anything back. If there's something that will make you happy, you know you can tell me, right?"_

 _Their sudden proximity made Killua swallow. Gon's question swirled through his thoughts._

 _Something that will make him happy. Something he wants…?_

 _Against his will, his heartbeat picked up momentum, as if he had just realized the answer and was now panicking to conceal it. Killua averted his gaze. Truth is…_

 _Truth is..._

 _Killua took in a breath. He decided he is already happy. He has nothing to ask for, because everything he wanted he had already gotten. A friend._

 _He did not know how to say any of this though, and by the time Killua had some half-excuse ready, the narrow space between them had already thinned to a hair. His words went unfinished. Gon never let him finish._

 _His eyes widened at the contact. At that point, Killua was convinced this was another dream._

 _If so, please let him dream a little longer._

.

Gon bolts upright, a little too fast. Wincing, he clutches his head, trying to make out the disorienting shape by his side.

"You're awake."

"Kurapika...?"

Kurapika sets aside his book, in favor of fetching Gon a glass of water. "Easy there."

Kurapika fills him in on what happened. The collapse, the hospital, the poison. It gave Leorio a scare, and Kurapika too. He flew over as soon as he heard, just in case there was something his nen could do that medicine could not. Thankfully, it did not have to come to that.

"And Killua?"

"Ah, he was the one who tracked down which poison had entered your system. It was because of him we got the antidote to you in time."

At this, Gon brightens, unable to hold back a smile. He knows he can always count on Killua. "Where is he now?

Kurapika hesitates, and Gon is left wondering why they have lost eye contact.

Somewhere in the far distance, a phone is vibrating. The call goes to voicemail.

Gon lowers his cellphone. His arm falls listless, his head spinning.

Chains restrain him midair, pulling him back before he could jump out the window. To Kurapika's relief, Gon has not recovered enough to snap free of them.

Leorio drops his suitcase when he hears yelling from down the hallway.

"Gon, you're awake!" His mirth is dampened by the scene that greets him. Kurapika makes a silent plea for help, while Gon screams against his restraints some more.

"Stop it, I have to help Killua!" Gon turns to Leorio with angry tears. "You're his friends. How could you just let him go like that!"

Of course they didn't. They tried. They tried to reason with him, but Killua made his decision.

For Gon, that is not enough. He could not sit still while his best friend was forced into doing something he hated, something that would hurt him.

"Gon! You have to understand that Illumi was not the one to call Killua. Killua called him. This was Killua's decision." Leorio softens. "And he decided your safety mattered more than anything else."

Gon stifles his words. He clutches the bedsheets. Damn it! Damn it...

Sighing, Kurapika falls back into his chair. What is done is done. Knowing Illumi, there is probably a vow between the Zoldyck brothers. It is probably best that Gon cannot interfere.

Damn it. Damn it! "DAMN IT!"

The chains break. Gon extends a hand, demanding Kurapika's phone. He will reach Killua even if it's the last thing he does.

.

 _"W-what was that for?"_

 _"You always look at me." It was a simple observation. "Like you want something, even if you don't say it."_

 _Gon smiled._

 _If Melody were here, she would hear a concerto. Gon did not know his own power, of his capacity to bring down the entire skies with a single gesture._

 _Gon's smile was broken by a poke to his forehead._

 _"Baka," Killua drawled, his expression one of clear annoyance. The flush in his cheeks had yet to disappear, but Killua regained enough of his senses to take control of the situation._

 _That was his job: to take control of the situation whenever Gon pushed too far. He had to reign the both of them in before Gon rendered him completely helpless._

 _Killua pocketed his hands, his language carefully crafted. Casual, but not dismissive. Distant, but friendly. He strained to keep a smile._

 _Gon might be onto something, but..._

 _"Don't decide for me what I want, okay?"_

 _Don't kiss him for a reason like that._

 _Just as Killua readied to turn around, Gon spoke up again._

 _"Wait, Killua-!"_

 _The poison brought him down faster than a shotgun to the head._

.

Killua looks at the number of unread messages on his phone before powering it off. Gon must have finally woken up. Killua is glad.

In the downpour, Killua turns his attention to the manor, and the light from inside. There had been no time to pack weapons. He would have to do this with his hands. The same hands that played clapping games with Gon, the same hands Gon held onto whenever he smiled at him, dragging him off to their next adventure.

A small bout of nausea courses through Killua, but he makes himself bear it. He just needs to bear this for a little while. Once it's done, he can forget everything and return to Gon. He just wants to return to Gon.

His mind blankens. The job Illumi gives him is not an easy one, and he cannot afford to think anymore.

In a flicker, he is perched outside the bedroom window.

It is a child's bedroom. The target sits on his bed, book open on his lap and glasses slightly akew. He will not see it coming. He will not feel anything.

There is not even a shift in shadow when the strike comes down.

Killua's nails stop a centimeter short.

His target remains unmoving, the book on his lap dotted with red, a single playing card caught in between the cracks.

Sitting amongst the collection of toys, a figure is holding out his phone. "Oh my, looks like someone is desperate to get in touch with you."

.

 _Sorry Killua._

 _Gon did not know why he deceived his friend like that. Truth is..._

 _Truth is, he had known for a long time._

 _More than that, he was relieved that Killua never brought it up. He was glad Killua chose not to. He was happy that despite everything, Killua was okay staying as his friend._

 _Just his friend and nothing more._

.

In the hospital room, Killua finds himself tackled to the ground.

Kurapika gives a helpless sigh, before smiling. Leorio waves to the doctor, before returning to inform everyone the good news. The poison is flushed out of Gon's system, no damage done. The only remaining point of concern is...

"How did it get there?" Leorio frowns. "Originally, we thought it was something in the food. But the poison Gon had is the instantaneous kind. It should have hit him within minutes of contact."

On the floor, Killua stiffens. He rolls Gon off him, his gaze averted.

"It came from me."

Everyone in the room looks to him in alarm, causing Killua to flinch.

"My training included poison to build up immunity. Some of them must have remained inside my body, and it must have… Gon must have got it from me," he finishes quickly.

Kurapika rubs his chin. "I see, that makes sense. So that's why you called Illumi, so he could tell you which ones to check."

"Yeah. Sorry I didn't tell everyone earlier. There was no time, and by the time the contract was formed…"

"... you didn't want us to weaken your resolve. We understand," Kurapika says.

Killua chuckles, grateful at how unbelievably lucky he is, to have friends as good as them. His smile weakens.

"Wait, what poisoned me?"

Everyone turns to Gon, who is still sporting a look of utter confusion.

"Were you at all listening? I did."

Gon directs his confusion towards Killua. "You? How?"

Killua feels the tinge of red creep up his cheeks. What the hell, does Gon need it spelled out for him?! "Y-you know, at the pier." He controls his sputtering, taking a deep breath. "Don't worry about it. I'll make sure to be more careful in the future, so that this doesn't happen again."

It will not happen again. Killua swears on this. He desperately needs to convince Gon that nothing has changed. Nothing has changed, he won't cause any trouble, so please just let them go back to before. He will prove that everything is okay, that Gon can still afford to keep him by his side and-

Their lips touch for the second time.

.

 _Gon hoped Killua would excuse his selfishness._

.

The cries for a nurse. The opening of a suitcase. The scrambling for another antidote. While everyone panics, Gon calmly sits in the center, content with himself.

It is only an hour later, when Gon remains perfectly well, that they finally listen to him.

"Like I said, it can't be Killua." If there were anything wrong with Killua, Gon would have smelled or tasted it on him. But Killua did not taste weird to him at all. In fact, he tasted very good!

While Killua is busy curling into himself, ready to die out of mortification, Gon continues. He did sense something weird back at the pier though, and he thought he felt something coming at them. He thought they were under attack by the Phantom Troupe. He thought they were going to target Killua too, whose guard was completely dropped that moment. Gon is happy that was not the case, because he would not know what he would do if he lost Killua.

Leorio closes his mouth, not sure what to say. He spares a glance at Killua, who has fallen silent.

Said silence is broken by a punch to the face.

"Wow, I am an idiot!" Killua says, squishing his cheeks. "I played right into Illumi's hands, didn't I. Tricking me into thinking I did it. Making me agree to that stupid job. Smart thinking on calling for Hisoka's help, Gon."

Gon smiles. "Yeah, good thing he likes me. If we're lucky, he might just confront Illumi and kill him for us!" He pauses, then turns to Killua. "Oh sorry, I forgot Illumi is your brother, Killua. I didn't mean it that way. I don't want him to die if it'll make you sad."

"Oh trust me, I'll live." Killua is nearly laughing, because Gon has done it again. Every time Illumi tries to sink him back down, Gon pulls him back up. Up into his world, where everything is sensical and _right_ again.

Illumi probably thinks he's succeeded. That Killua now thinks he's unfit to be Gon's friend. That his body is toxic. That his desires are dangerous. That the next time he tries kissing anyone, the only thing he will think about is the comatose body of his former best friend, how he was guilty and he was responsible. Illumi probably thinks it would only be a matter of time until Killua realizes the underground world is his proper place.

Illumi has no idea how wrong he is, as Killua is laughing, still mostly red from embarrassment. His fantasy of kissing Gon is ruined, but mostly because it turned into a spectacle and he cannot rid Leorio's ridiculous expression from his mind.

Most importantly - and he tries to not let any tears slip through his chuckles - he knows now his friendships are not flimsy things he should worry of being lost. Leorio and Kurapika are there. They have his back. And Gon…

All Killua can think is how lucky he is.

.

"So let me get this straight," Killua says, removing the ice cream spoon from his mouth. "You want to continue kissing. Not because you return my feelings, or because you want to satisfy my feelings, but because you think it's fun."

Gon nods enthusiastically. "You taste good, and I feel happy, and my heart goes crazy. Kissing Killua is really exciting!"

"Not so loud," Killua hisses under his breath, shielding his face from passing pedestrians. Any redder, and he will be indistinguishable from the color of his shirt.

Popping another scoop of ice cream into his mouth, he mulls over Gon's proposal. Not that there is anything to mull over. Killua already knows he will go along with whatever Gon says.

Gon has just been released from a two-week hospitalization. He is at risk of getting gunned down by the most infamous assassins in the world. And instead of running for the hills, he is grabbing frozen dessert with Killua. If Gon can deal with his crazy family issues, Killua can deal with a few eccentric requests.

"Okay," Killua says, lowering his spoon. At Gon's beam, he adds, "But! I'm putting down some ground rules. One, not in public."

"You don't want people to see us?"

 _You want them to?_ Killua mentally asks, sweating profusely at Gon's almost disappointed look. Oh gods, this is probably part of the thrill for him.

"No, because as our first time has shown, I get distracted. Kissing is… distracting. With the Phantom Troupe and my family and whoever else after us, it's best that I remain fully aware of our surroundings whenever we're venturing out."

Gon seems to understand, as his expression changes to one of full agreement. "Okay, yes, that makes sense. And I don't want Killua thinking about other people when we do it either."

Killua swallows. Gon really does not intend to make this easy for him, does he. "Two, whenever we d-do it, and I react in way you don't like, you'll let me know, okay? I don't want to make anything awkward between us."

Gon nods. "Got it. And three?"

Does Killua have a three? The longer he looks at Gon, the more he wonders how he still capable of coherent thoughts, much less words. "No, that's it."

Gon settles back in his seat. "Okay, I have a few rules too. But first, do you want grill or barbecue for dinner?"

Killua blinks, before resting his cheek in his palm. "I guess barbecue."

"Alright, then I'm treating Killua to barbecue for dinner, the best in Yorkshin!"

"What, you don't-"

"And after, I'll take you somewhere really fun, with lots of beautiful lights!"

"Sure, but what-"

"And after that, I'll walk you back home!"

Killua feels his eye twitch, before slamming the rest of his ice cream in Gon's face. "We live in a hotel. The _same_ hotel, _baka_."

"Then I'll walk you back to your room!" Gon says, unfazed by the ice cream dripping down his face.

"Our rooms are a foot apart!"

"I'll walk that foot with you!"

"What is even the purpose of that?!"

"Because that's one of the rules! Now that I get to kiss Killua, I have to do all the proper things! Oh, I would need to dress up too..." Gon says, pulling on the collar of his jacket.

"Since when did I agree to a date?!"

"Huh? We're not dating."

"You-" Killua is sputtering again.

Gon smiles. "I just want to do all types of fun and exciting things together. Is that okay with you, Killua?"

Killua stares some more, mouth slightly ajar, before he is forced to break away from Gon's gaze.

That is okay with Killua. In fact, it would make him really... happy.

.

The hallway is loud with laughs and tumbles.

"Wait, Gon, close the door firs-"

The door slams shut, though Kalluto's trained ears could still pick up faint noises from inside the hotel room. Their mission has failed. Kalluto looks down at his fan, regretting not killing Gon back at the pier.

Father had been strict on no one killing Gon. Killua is not the most rational person, and his current state of mind is delicate. Taking away the object of his affection could push him away from the family forever. Besides, Silva is convinced the outside world would be good for Killua's emotional growth and maturity. A person needed to be torn down now and then to be strong.

Unfortunately, Kalluto shares more of his mother's worries than his father's confidence. From what he has observed the past weeks, it is clear Gon is not healthy for Killua. Worse, Killua is showing the symptoms of an addiction. The dilation in his eyes, the shaking in his breath, the increasing recklessness and submission…

Kalluto fades back into the shadows. He needs to get stronger to bring Killua back home. His brother is too blinded to see how dangerous Gon is.

Gon is poison, and for once, Killua is not immune.


End file.
